Setup: I'm trying to make the band structure for a planar photonic crystal with finite thickness, i.e., a quasi-3D problem. I only want the x-direction band structure. So, I'm using variable floquet periodic BCs for the x-direction boundaries, and 0 degree floquet periodic BCs for the y-direction. The top and bottom parts of the cell have either PEC or PMC BCs. I'm trying to adapt the method used here: http://www.comsol.com/showroom/documentation/model/798/ This tutorial shows how to a make band diagram for a purely 2D photonic crystal. The main idea in the tutorial is following a particular band while ramping k by force feeding the previous frequency into the current parametric solver. Their method also uses an integration coupling variable with an ODE on the frequency, by normalizing the z-comp of the electric field (they're using 2D > RF Module > In-Plane Wave > TE waves > eigenfrequency). Problem: I try to adapt the problem by normalizing the entire electric field using: Ex*conj(Ex) + Ey*conj(Ey) + Ez*conj(Ez). For subdomain ICs I use Ex(to) = Ex, etc., for all parts of the E-field. When I try to run the parametric solver and ramp k, the solver immediately halts, saying that it doesn't know what Ex, Ey, and Ez are. Any ideas?